The trial was carried out in 1,349 healthy subjects aged 18 to 64, in 28 Canadian sites, between October 2003 and May 2004. Both one- and two-dose FluINsure regimens were efficacious in preventing influenza-like illness (two or more symptoms) in association with a positive influenza virus culture. No FluINsure recipient experienced febrile illness associated with culture-confirmed influenza.
The immunogenicity data from the study showed a significant rise in serum hemagglutination-inhibiting (HAI) antibody titers, a widely accepted correlate of protection against influenza disease, when vaccinees were compared to placebo recipients.
The increases in HAI titers were highly significant for all three vaccine viruses (A/H1N1, A/H3N2, and B). The increases were statistically indistinguishable between vaccinees who received two doses and those who received a single dose of FluINsure. In addition, significant rises in salivary secretory IgA specific for the vaccine viruses were also found for all three vaccine viruses among subjects who received the active vaccine, but not those who received placebo.
Salivary secretory IgA responses were not significantly different between subjects who received the two dose regimen and those who received one dose.
With regard to safety, there was no statistically significant association of local or respiratory complaints with active vaccine when compared with placebo (saline). Similarly, neither temperature elevations nor systemic complaints were related to receipt of FluINsure at either dosage level.
Throughout the study period, there was no statistically significant difference in the overall incidence of adverse events reported between the vaccine and placebo groups, and there was no significantly increased rate of any particular class of adverse events in vaccine recipients versus placebo recipients.
“These are very encouraging results,” commented Dr Louis Fries, vice president of clinical and medical affairs. “The immunogenicity trends that we showed in smaller studies have been validated, and we have shown immune responses to the single-dose regimen that are in agreement with its efficacy.”
ID Biomedical also announced that it has completed enrollment of a reimmunization study in Canada, testing FluINsure formulated with the flu antigen acquired through the company’s purchase of Shire Pharmaceuticals’ vaccine assets. All subjects have been enrolled and have received a single dose of FluINsure.
The objective of this study is to demonstrate that the vaccine is well tolerated and gives a strong immune response in those persons who have received the vaccine in the previous flu season. ID Biomedical expects to have results of this study in spring 2005 and plans to initiate its first pediatric clinical studies of FluINsure in the US towards the end of 2005.